It is known since long that batteries used for driving a vacuum cleaner need to be cooled to be used as efficiently as possible and to last as long as possible. One way of cooling them is to lead the air flow created by the vacuum cleaner past the batteries.
It has also been known since long to make stick or upright type vacuum cleaners in two parts connectable to each other in order to save space when the vacuum cleaner is stored or transported. Different solutions exist, such as making the vacuum cleaner in two separate parts connectable to each other by the user, or to make the vacuum cleaner in two different parts connected to each other via a knee joint such that the user can fold and unfold the cleaner in order to adapt it for cleaning purposes or for storing.
There has also since long been a wish to increase the battery capacity to have a longer running time and to have enough power for the fan unit to create large air flows. Also with new battery technologies is has been difficult to fit enough batteries into the vacuum cleaners to reach the desired levels regarding running time and air flow.